Impatiens wuerstenii S.B. Janssens & Dessein, 2018

Janssens, Steven B., Ballings, Petra, Mertens, Arne & Dessein, Steven, 2018, A new endemic Impatiens species on Mount Gorongosa (Mozambique) demonstrates the conservation importance of montane areas in Africa, Phytotaxa 333 (1), pp. 73-85 : 75-77

publication ID	https://doi.org/ 10.11646/phytotaxa.333.1.5
persistent identifier	https://treatment.plazi.org/id/9A4987B5-A54E-FFC0-4FBA-FA0BFDE2FAA7
treatment provided by	Felipe
scientific name	Impatiens wuerstenii S.B. Janssens & Dessein
status	sp. nov.

Treatment

Impatiens wuerstenii S.B. Janssens & Dessein View in CoL sp. nov.

I. wuerstenii differs from I. psychadelphoides in having well developed, oblong-shaped, distinctly apiculate upper lateral petals that are half the size of the lower lateral petals, as well as ovate-triangular lateral sepals, and elliptic to subovate leaves with attenuate to narrowly acute leaf bases.

Type: — MOZAMBIQUE. Sofala Province: Gorongosa Mountains , 18.438556 S, 34.044831 W, 1744 m, 31/12/2011, Ballings 1713 (holotype BR, isotype WAG, MO; Figs. 1A View FIGURE 1 & 2 View FIGURE 2 ) GoogleMaps .

Perennial herb; stems erect, branched, to 1 m tall, pubescent above, glabrescent below. Leaves spirally arranged; petiole 0.7–2 cm long, pubescent; leaf blades elliptic, more rarely subovate, 4.5–8.6 by 2.2–3.5 cm, sparsely pubescent on the veins above, more densely pubescent underneath; leaf apex acute or shortly acuminate; leaf base attenuate or narrowly acute; leaf margin crenate-dentate with teeth up to 2 mm long; lateral veins 6–8 at both sides of the mid-vein. Flowers solitary, pink; bracts at the base linear-subulate, to c. 3 mm long; pedicels 3.5–5.5 cm long, pubescent; lateral sepals narrowly ovate-triangular, 4.5–5 by 1.5–2 mm, glabrous inside, pubescent outside; lower sepal navicular, abruptly constricted into a narrow spur, c. 11 mm long, 7.5 mm deep, with the spur 3.7–4 cm long, more densely pubescent at the base; dorsal petal broadly ovate to almost circular, deeply emarginate, dorsally with a narrow crest terminating in a distinct acute projection at the apex, 10–12 mm by 11–12 mm, glabrous inside, with a few hairs outside particularly on the crest; lateral united petals c. 19 mm long; upper petal elliptic oblong, distinctly apiculate, 10–12 by 5 mm, about half the size of the lower petal; lower petal 16–17 by 8 mm, glabrous inside and outside. Ovary glabrous. Fruits unknown.

Phenology: — Impatiens wuerstenii flowers at least in December and January.

Distribution and ecology: — Impatiens wuerstenii is endemic to Mozambique, where it is only found on Mount Gorongosa (type collection; Fig. 3 View FIGURE 3 ). The new species grows in a restricted habitat between 1700 and 1800 m at the margins of montane grasslands and patches of forest or ericoid shrub. Often found among rocks, usually in half-shaded environment.

Etymology: —The species epithet wuerstenii refers to the collector of the new species: Bart Würsten.

Additional specimens examined: — MOZAMBIQUE: Sofala Province: Gorongosa Mountains , 18.443172 S, 34.048494 W, 1725m, 31/12/2011, Ballings 1712 ( BR) GoogleMaps ; 18.438703 S, 34.044775 W, 1746m, 31/12/2011, Ballings 1714 ( BR) GoogleMaps ; 18.439103 S, 34.044683 W, 1752m, 31/12/2011, Ballings 1715 ( BR) GoogleMaps ; 18.439581 S, 34.044522 W, 1760m, 31/12/2011, Ballings 1716 ( BR) GoogleMaps .

Conservation status:—The species has only been collected on Mount Gorongosa. Human pressure in the region is significant and results in the degradation and destruction of forested areas ( Müller et al. 2012). Because of the restricted distribution range of I. wuerstenii , we would apply the category of “vulnerable” under criterion D2 (less than five locations). Human activities can make the species become critically endangered or even extinct within a rather short period of time ( IUCN 2001).